For nearly seven years, Dale Liuzza raised his son as the caregiving parent in a gay relationship. The boy was conceived through a surrogate, a donor egg and a mixture of sperm from both his dads.

"We didn't know or care about the biology," said Liuzza, 31, and a behavioral therapist who works with autistic children in New Orleans. "I pretty much raised him. As far as I was concerned, I carried him."

But when the men's relationship fell apart, his partner determined he was the biological father and took the boy out of state to Texas and eventually to Washington State.

Louisiana does not recognize same-sex marriage or second-parent adoption, so Liuzza was left with no legal parental rights.

"I never imagined he would move out of state and I would have no say in the matter at all," he said. "I don't sleep at night thinking about [the child]."

In more than 30 states, children in LGBT [lesbian, gay, bisexual and transgender] families are legal strangers to at least one of their parents.

In Louisiana, for example, Liuzza would have to be the biological parent or legally married to his partner to secure parenting rights. Same-sex marriage is illegal in that state and two men's names cannot appear on the birth certificate.

Between 2 million and 2.8 million children are being raised by LGBT parents, and because of a patchwork of state laws and no federal protections, many of these children are at risk, according to the report by the Movement Advancement Project, Family Equality Council, Evan B. Donaldson Adoption Institute, the Equality Foundation and the Center for American Progress.

In the United States, 69 percent of children live with married, heterosexual parents, down from 83 percent in 1970, according to the report. Today, an estimated 24 percent of female same-sex couples, 11 percent of male couples and 38 percent of transgender Americans are raising children.

While states like California and New York have high numbers of same-sex couples, those most likely to be raising children live in Mississippi, Wyoming, Alaska, Arkansas, Texas, Louisiana, Oklahoma, Kansas, Alabama, Montana, South Dakota and South Carolina, in that order.

A second legal parent may be unable to pick up a child from day care without authorization or advocate for a child in school. In these states, nonbiological same-sex parents cannot include a child on their health insurance and can be denied access to a hospital in an emergency or be left out of health care decisions.

Inconsistent laws make it difficult even for families from states where same-sex marriage and second-parent adoption is legal when they cross state lines, according to the report.

"If a couple in Washington, a state with full parental recognition, goes on vacation jet skiing in Idaho and the kid gets hurt, one parent might not be recognized," said Calla Rongerude, spokesman for the Movement Advancement Project, an LGBT think tank, and one of the co-authors of the report.

"If you are a New York family visiting Philadelphia, you better take everything you have and hope there is a sympathetic nurse when you have to go to the hospital," she said.

Children are also unable to access death or disability benefits or government safety net programs from a non-legal parent. They can lose inheritance and other protections designed to keep them safe during times of crisis, according to the report.

"When we talk about ballot measures on marriage, we don't talk about the kids," said Rongerude. "And frankly, they are the most vulnerable."

Gay Couples Challenge North Carolina Law

In North Carolina, for example, second-parent adoptions for same-sex couples were outlawed in 2010. Only stepparents who are legal spouses or the biological parent can adopt. Gay marriage is not legal in that state.

Even those couples who lived in "friendly counties" around the state's urban centers who previously had such rights, had them revoked when a judge invalidated their adoptions.

When LGBT families are banned from being foster parents or adopting, children are denied permanent homes and remain in state care instead, according to studies from the Evan B. Donaldson Adoption Institute.

"The best interests of children should always be paramount," said its executive director, Adam Pertman, in a prepared statement. "With more than 400,000 children in foster care and more than 100,000 children awaiting adoption, it simply makes no sense -- and certainly isn't to their benefit -- to deny children a forever home with qualified and loving parents simply because those parents are gay or unmarried."

In widely different policy, California allows same-sex couples to pursue second-parent adoption. Going one step further, the state Senate is expected to pass a law allowing multiple parents to act on a child's behalf, as an effort to keep children out of foster care in case of death or divorce.

The bill sprang from a 2011 appellate court decision that placed a girl in foster care when her legally married parents -- two lesbians -- could not care for her. The child was taken into state custody when one of her mothers was jailed and the nonbiological mother was hospitalized.

The court did not have the authority to appoint the girl's biological father, with whom she had a relationship, as a legal parent.

As for Liuzza, he never dreamed his son would be taken away. "I thought we were equal like everyone else," he said.

But after he initiated a separation because of problems in the relationship, Liuzza said his partner sought genetic testing.

Just before the boy's sixth birthday, his partner used his rights as the legal parent to take the child away.

"I showed up at school one day to pick [the boy] up and he wasn't there," said Liuzza. "I called my ex and he was on a plane to Dallas. The school had no idea. My son had no idea. I had no idea."

Now, he only sees his son once every two months and his ex-partner times the phone calls to 20 minutes twice a week. Although Liuzza has generous health benefits, his ex-partner does not, and the child hasn't seen a doctor or dentist in months.

In California, where he has gay friends who both have legal rights, Luizza said, "if David and David separated, they would be able to fight it in court."

"It's the hardest thing," he said. "And the only way I can get through it is knowing that when my son is 16 or 17, he can make the decision where he wants to live."

Liuzza hired two lawyers and spent "so much money" to make himself a legal parent, but to no avail.

"I couldn't do it," he said. "I am virtually a stranger … Frankly, biology in this state is more important than experience and caregiving."